1
2
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <signal.h>
6 #include "tests/sys_mman.h"
7
sig_handler(int sig)8 void sig_handler(int sig){
9 int var;
10 fprintf(stderr, "caught signal, local var is on %p\n", &var);
11 }
12
main(int argv,char ** argc)13 int main(int argv, char** argc) {
14 int res, i;
15 stack_t sigstk;
16 struct sigaction act;
17 static const int size = SIGSTKSZ*2;
18 // We give EXEC permissions because this won't work on ppc32 unless you
19 // ask for an alt stack with EXEC permissions,
20 // since signal returning requires execution of code on the stack.
21 char *stk = (char *)mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC,
22 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
23 sigstk.ss_sp = stk;
24
25 sigstk.ss_size = size;
26 sigstk.ss_flags = 0;
27 fprintf(stderr, "calling sigaltstack, stack base is %p\n", sigstk.ss_sp);
28 if (sigaltstack(&sigstk,0)<0) perror("sigaltstack");
29
30 fprintf(stderr,"setting sigaction\n");
31 act.sa_flags=SA_ONSTACK;
32 act.sa_handler=&sig_handler;
33 sigemptyset(&act.sa_mask);
34 res = sigaction(SIGUSR1,&act,0);
35 fprintf(stderr, "res = %d\n", res);
36 fprintf(stderr, "raising the signal\n");
37 raise(SIGUSR1);
38
39 /* Loop long enough so valgrind has a forced context switch and
40 actually delivers the signal before the thread exits. */
41 for (i = 0; i < 1000000; i++) ;
42
43 fprintf(stderr, "done\n");
44 return 0;
45 }
46